/*

Copyright (c) 2014-2020, Arvid Norberg
Copyright (c) 2016, Andrei Kurushin
Copyright (c) 2016, Eugene Shalygin
Copyright (c) 2017, Steven Siloti
Copyright (c) 2018, Alden Torres
All rights reserved.

You may use, distribute and modify this code under the terms of the BSD license,
see LICENSE file.
*/

#include "libtorrent/session.hpp"
#include "libtorrent/session_settings.hpp"
#include "libtorrent/alert_types.hpp"
#include "libtorrent/time.hpp"
#include "libtorrent/random.hpp"
#include "libtorrent/session_params.hpp"
#include "libtorrent/aux_/path.hpp"
#include <iostream>
#include <tuple>

#include "test.hpp"
#include "setup_transfer.hpp"
#include "settings.hpp"
#include "swarm_suite.hpp"

#ifdef _MSC_VER
#pragma warning(push)
// warning C4706: assignment within conditional expression
#pragma warning( disable : 4706 )
#endif

void test_swarm(test_flags_t const flags)
{
	using namespace lt;

	std::printf("\n\n ==== TEST SWARM === %s%s%s%s%s%s%s ===\n\n\n"
		, (flags & test_flags::super_seeding) ? "super-seeding ": ""
		, (flags & test_flags::strict_super_seeding) ? "strict-super-seeding ": ""
		, (flags & test_flags::seed_mode) ? "seed-mode ": ""
		, (flags & test_flags::time_critical) ? "time-critical ": ""
		, (flags & test_flags::suggest) ? "suggest ": ""
		, (flags & test_flags::v1_meta) ? "v1-meta ": ""
		, (flags & test_flags::v2_meta) ? "v2-meta ": ""
		);

	// in case the previous run was terminated
	error_code ec;
	remove_all("tmp1_swarm", ec);
	remove_all("tmp2_swarm", ec);
	remove_all("tmp3_swarm", ec);

	// these are declared before the session objects
	// so that they are destructed last. This enables
	// the sessions to destruct in parallel
	session_proxy p1;
	session_proxy p2;
	session_proxy p3;

	settings_pack pack = settings();
	pack.set_bool(settings_pack::allow_multiple_connections_per_ip, true);

#if TORRENT_ABI_VERSION == 1
	if (flags & test_flags::strict_super_seeding)
		pack.set_bool(settings_pack::strict_super_seeding, true);
#endif

	if (flags & test_flags::suggest)
		pack.set_int(settings_pack::suggest_mode, settings_pack::suggest_read_cache);

	// this is to avoid everything finish from a single peer
	// immediately. To make the swarm actually connect all
	// three peers before finishing.
	float const rate_limit = 100000;

	int const port = static_cast<int>(lt::random(100));
	char iface[50];
	std::snprintf(iface, sizeof(iface), "0.0.0.0:480%02d", port);
	pack.set_int(settings_pack::upload_rate_limit, int(rate_limit));
	pack.set_str(settings_pack::listen_interfaces, iface);
	pack.set_int(settings_pack::max_retry_port_bind, 1000);

	pack.set_int(settings_pack::out_enc_policy, settings_pack::pe_forced);
	pack.set_int(settings_pack::in_enc_policy, settings_pack::pe_forced);

	lt::session ses1(pack);

	std::snprintf(iface, sizeof(iface), "0.0.0.0:490%02d", port);
	pack.set_str(settings_pack::listen_interfaces, iface);
	pack.set_int(settings_pack::download_rate_limit, int(rate_limit / 2));
	pack.set_int(settings_pack::upload_rate_limit, int(rate_limit));
	lt::session ses2(pack);

	std::snprintf(iface, sizeof(iface), "0.0.0.0:500%02d", port);
	pack.set_str(settings_pack::listen_interfaces, iface);
	lt::session ses3(pack);

	add_torrent_params p;
	p.flags &= ~torrent_flags::paused;
	p.flags &= ~torrent_flags::auto_managed;
	if (flags & test_flags::seed_mode) p.flags |= torrent_flags::seed_mode;
	// test v1 metadata using piece sizes smaller than 16kB
	int const piece_size = (flags & test_flags::v1_meta) ? 8 * 1024 : 16 * 1024;
	auto const [tor1, tor2, tor3] = setup_transfer(&ses1, &ses2, &ses3, true
		, false, true, "_swarm", piece_size, nullptr, bool(flags & test_flags::super_seeding), &p
		, true, false, nullptr
		, (flags & test_flags::v1_meta) ? create_torrent::v1_only
		: (flags & test_flags::v2_meta) ? create_torrent::v2_only
		: create_flags_t{});

	if (flags & test_flags::time_critical)
	{
		tor2.set_piece_deadline(piece_index_t(2), 0);
		tor2.set_piece_deadline(piece_index_t(5), 1000);
		tor2.set_piece_deadline(piece_index_t(8), 2000);
	}

	float sum_dl_rate2 = 0.f;
	float sum_dl_rate3 = 0.f;
	int count_dl_rates2 = 0;
	int count_dl_rates3 = 0;

	for (int i = 0; i < 80; ++i)
	{
		print_alerts(ses1, "ses1");
		print_alerts(ses2, "ses2");
		print_alerts(ses3, "ses3");

		torrent_status st1 = tor1.status();
		torrent_status st2 = tor2.status();
		torrent_status st3 = tor3.status();

		if (flags & test_flags::super_seeding)
		{
			TEST_CHECK(st1.is_seeding);
			TEST_CHECK(tor1.flags() & torrent_flags::super_seeding);
		}

		if (st2.progress < 1.f && st2.progress > 0.5f)
		{
			sum_dl_rate2 += st2.download_payload_rate;
			++count_dl_rates2;
		}
		if (st3.progress < 1.f && st3.progress > 0.5f)
		{
			sum_dl_rate3 += st3.download_rate;
			++count_dl_rates3;
		}

		print_ses_rate(float(i), &st1, &st2, &st3);

		if (st2.is_seeding && st3.is_seeding) break;
		std::this_thread::sleep_for(lt::milliseconds(1000));
	}

	TEST_CHECK(tor2.status().is_seeding);
	TEST_CHECK(tor3.status().is_seeding);

	float average2 = count_dl_rates2 > 0 ? sum_dl_rate2 / float(count_dl_rates2) : -1;
	float average3 = count_dl_rates3 > 0 ? sum_dl_rate3 / float(count_dl_rates3) : -1;

	std::cout << "average rate: " << (average2 / 1000.f) << "kB/s - "
		<< (average3 / 1000.f) << "kB/s" << std::endl;

	if (tor2.status().is_seeding && tor3.status().is_seeding) std::cout << "done\n";

	// make sure the files are deleted
	ses1.remove_torrent(tor1, lt::session::delete_files);
	ses2.remove_torrent(tor2, lt::session::delete_files);
	ses3.remove_torrent(tor3, lt::session::delete_files);

	alert const* a = wait_for_alert(ses1, torrent_deleted_alert::alert_type, "swarm_suite");

	TEST_CHECK(alert_cast<torrent_deleted_alert>(a) != nullptr);

	// there shouldn't be any alerts generated from now on
	// make sure that the timer in wait_for_alert() works
	// this should time out (ret == 0) and it should take
	// about 2 seconds
	time_point start = clock_type::now();
	alert const* ret;
	while ((ret = ses1.wait_for_alert(seconds(2))))
	{
		std::printf("wait returned: %d ms\n"
			, int(total_milliseconds(clock_type::now() - start)));
		std::vector<alert*> alerts;
		ses1.pop_alerts(&alerts);
		for (auto ap : alerts)
		{
			std::printf("%s\n", ap->message().c_str());
		}
		start = clock_type::now();
	}

	std::printf("loop returned: %d ms\n"
		, int(total_milliseconds(clock_type::now() - start)));

	// this allows shutting down the sessions in parallel
	p1 = ses1.abort();
	p2 = ses2.abort();
	p3 = ses3.abort();

	time_point const end = clock_type::now();

	std::printf("time: %d ms\n", int(total_milliseconds(end - start)));
	TEST_CHECK(end - start < milliseconds(3000));
	TEST_CHECK(end - start > milliseconds(1900));

	TEST_CHECK(!exists("tmp1_swarm/temporary"));
	TEST_CHECK(!exists("tmp2_swarm/temporary"));
	TEST_CHECK(!exists("tmp3_swarm/temporary"));

	remove_all("tmp1_swarm", ec);
	remove_all("tmp2_swarm", ec);
	remove_all("tmp3_swarm", ec);
}

#ifdef _MSC_VER
#pragma warning(pop)
#endif
